Fiddle-leaf fig tree needed more time to recuperate from transplant

I moved my dying fiddle-leaf fig to a sunnier area a few months ago, but it did not get better. I repotted it recently and the branches exposed to morning sun started growing new leaves, but they were tiny with brown spots on the edges, and fell off quickly. The lower parts of the plant, which are shaded by the wall and do not get sunlight, sprouted lush and healthy leaves. How do I get the leaves on the upper branches to grow as well? I water and fertilise the plant about once every 10 days.

Ros Yip

From the picture, the plant is showing new growth, which is good news.

When did the new leaves die? Was it after you repotted the plant? Depending on the amount of root disturbance during the repotting process, the plant may suffer from transplant shock, and exposure to sunlight can cause leaves to wilt and turn brown due to excessive loss of water. The portions in the shade will suffer less due to the cooler conditions.

When transplanting a plant, it is best to put it in a shadier and cooler spot for it to recuperate for a couple of days. Avoid placing it in a windy spot or doing anything else that can dry the plant out. Water the plant regularly to ensure the root zone is kept moist at all times. Feed it with fertiliser only when it shows new, robust growth.

Frangipani suffering from rust disease

I transplanted my frangipani into the ground, but the leaves look infected. Fungicide and insecticide do not work. What should I do?

Lee Teck Tiam

The brown spots on the underside of your plant’s leaves are typical of the rust disease that often affects frangipani. It is caused by a fungus, which can be difficult to treat with commonly available fungicides. 

Remove and discard all infected leaves. Do not compost them. Spray the plant with fungicide to protect other leaves before any other signs of disease appear. You can use a copper-based fungicide such as copper oxychloride or systemic ones like myclobutanil. The former is a contact-based fungicide that needs to be reapplied after heavy rain as it gets washed away.

Begonia looks sunburnt

The tips of my begonia’s leaves have started to dry and shrivel up, while some leaves have brown patches. Why is this happening? The plant is in a pot on my balcony and gets sunlight all day. I fertilise it with pellets about once a month.

Joyce Ho

Was the begonia growing in a shaded spot before being moved to an area with direct sunlight? The direction of sunlight changes over the year and the sudden increase in sunlight can be too intense, which may have burned the leaves. The hotter conditions can also dry the plant out much faster.

Begonias grow best in a shaded or semi-shaded spot that is protected from the elements, depending on the cultivar. You may want to shift your plant to a shadier spot during the sunnier times of the year. Ensure the plant does not dry out and wilt.

Another possibility is fertiliser burn from the pellets. Begonias are herbaceous plants and excessive fertiliser can burn their tissues easily. You may want to remove some of the pellets and flush the root zone to remove excessive salts. For new fertilisers, it is advisable to use less at the start in case the plant has an adverse reaction.

Ensure desert rose does not dry out completely

The leaves of this plant are turning more yellow each day. They then dry up and fall off. What is wrong?

Rosalind Soh

Make sure your desert rose plant gets at least six hours of direct sunlight a day. Its new growth looks stretched, indicating a lack of light. Although this plant is drought-tolerant, do not let it dry out completely for long periods. The prolonged lack of water can cause leaves to turn yellow and die. Pot the plant in a well-draining growing mix containing burnt earth and let it dry out slightly before watering again.

Alocasia does not tolerate wet feet

My plant was thriving and had healthy leaves a year ago, but lately the leaves have been turning yellow. What is wrong? It gets filtered light from my window.

Tan Chay Kheng

It appears that your alocasia plant is growing in a cocopeat-based medium, which is able to keep the root zone moist for long periods. Alocasias do not tolerate wet feet, which can cause the plant to rot. Make sure the yellowed portions of the plant are not soft and mushy at the base.

Remove all rotting portions of the plant. If part of the corm is still intact, let it dry and heal before potting up in well-draining growing media. Most hobbyists grow their alocasias in an aerated mix of shredded pine bark, perlite and pumice.

Check for the presence of spider mites, which are sap-sucking pests commonly found on this plant. You can wipe the pests from the leaves using a wet cloth. Mist your plants regularly to maintain humidity and to wash away dust and smaller pests. Spray your plants with a very diluted soap solution to suffocate small, sap-sucking pests when they appear.

• Answers by Dr Wilson Wong, an NParks-certified practising horticulturist, parks manager and ISA-certified arborist. He is the founder of Green Culture Singapore and an adjunct assistant professor (Food Science & Technology) at the National University of Singapore.
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